ALAN SCHER ZAGIER, Associated Press

BERKELEY, Mo. (AP) — Protesters have dispersed after a failed attempt to block part of Interstate 70 near the St. Louis suburb where a police officer fatally shot unarmed 18-year-old Michael Brown.

The planned rush-hour traffic shutdown fell through Wednesday after a wall of officers in riot gear blocked demonstrators from walking onto the highway.

Officers from the city, county and Missouri Highway Patrol warned the roughly 150 demonstrators to stay off a road near a highway on-ramp. Those who refused were arrested.

Sgt. Al Nothum of the state Highway Patrol says 35 people were arrested. Nothum also says protesters threw rocks, concrete blocks and bricks.

Organizers said the protest was designed as an act of nonviolent civil disobedience.